From 4ac29817a26e8917bb7b395c3aee53bac3ccc14a Mon Sep 17 00:00:00 2001
From: spastorelli <spastorelli@users.noreply.github.com>
Date: Mon, 16 Mar 2026 16:00:31 +0100
Subject: [PATCH] Expose a ~gitbook/auth/login URL to handle redirection to
 upstream auth with current location passed (#4113)

---
 bun.lock                                      |   5 +-
 package.json                                  |   2 +-
 .../[siteData]/~gitbook/auth/login/route.ts   |  30 +++++
 .../components/DocumentView/InlineButton.tsx  |  37 +++---
 .../src/components/Header/HeaderLink.tsx      | 119 +++++++++++-------
 .../src/components/Header/HeaderLinkMore.tsx  |  35 +++---
 .../primitives/SiteAuthLoginLink.tsx          |  76 +++++++++++
 .../gitbook/src/lib/auth-login-link.test.ts   |  85 +++++++++++++
 packages/gitbook/src/lib/auth-login-link.ts   |  36 ++++++
 packages/gitbook/src/lib/sites.ts             |   8 +-
 packages/gitbook/src/middleware.ts            |   3 +-
 11 files changed, 354 insertions(+), 82 deletions(-)
 create mode 100644 packages/gitbook/src/app/sites/dynamic/[mode]/[siteURL]/[siteData]/~gitbook/auth/login/route.ts
 create mode 100644 packages/gitbook/src/components/primitives/SiteAuthLoginLink.tsx
 create mode 100644 packages/gitbook/src/lib/auth-login-link.test.ts
 create mode 100644 packages/gitbook/src/lib/auth-login-link.ts

diff --git a/bun.lock b/bun.lock
index a88481850..a287b4da3 100644
--- a/bun.lock
+++ b/bun.lock
@@ -1,6 +1,5 @@
 {
   "lockfileVersion": 1,
-  "configVersion": 0,
   "workspaces": {
     "": {
       "name": "gitbook",
@@ -349,7 +348,7 @@
     "react-dom": "catalog:",
   },
   "catalog": {
-    "@gitbook/api": "0.169.0",
+    "@gitbook/api": "0.170.0",
     "@scalar/api-client-react": "^1.3.46",
     "@tsconfig/node20": "^20.1.6",
     "@tsconfig/strictest": "^2.0.6",
@@ -746,7 +745,7 @@
 
     "@fortawesome/fontawesome-svg-core": ["@fortawesome/fontawesome-svg-core@7.1.0", "", { "dependencies": { "@fortawesome/fontawesome-common-types": "7.1.0" } }, "sha512-fNxRUk1KhjSbnbuBxlWSnBLKLBNun52ZBTcs22H/xEEzM6Ap81ZFTQ4bZBxVQGQgVY0xugKGoRcCbaKjLQ3XZA=="],
 
-    "@gitbook/api": ["@gitbook/api@0.169.0", "", { "dependencies": { "event-iterator": "^2.0.0", "eventsource-parser": "^3.0.0" } }, "sha512-kzJT8P5HCnqeYG3kFmBfvKMjQhTuUVmNV5Wvyh87QnoOA3odwh2C3qONpTmBA6cNE3ymDnxs8SJT9FG/qquRZQ=="],
+    "@gitbook/api": ["@gitbook/api@0.170.0", "", { "dependencies": { "event-iterator": "^2.0.0", "eventsource-parser": "^3.0.0" } }, "sha512-RCW9tipg8CJqXPHrZ65wj/EwN4/Rmvy4uOZ8tez5B9NcM7C4vYJOBcgsBeGD4bB5I0YmH/uyZMno5zgIM8sOKw=="],
 
     "@gitbook/browser-types": ["@gitbook/browser-types@workspace:packages/browser-types"],
 
diff --git a/package.json b/package.json
index 163b103ed..4b2e0ccfb 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,7 @@
         "catalog": {
             "@tsconfig/strictest": "^2.0.6",
             "@tsconfig/node20": "^20.1.6",
-            "@gitbook/api": "0.169.0",
+            "@gitbook/api": "0.170.0",
             "@scalar/api-client-react": "^1.3.46",
             "@types/react": "^19.0.0",
             "@types/react-dom": "^19.0.0",
diff --git a/packages/gitbook/src/app/sites/dynamic/[mode]/[siteURL]/[siteData]/~gitbook/auth/login/route.ts b/packages/gitbook/src/app/sites/dynamic/[mode]/[siteURL]/[siteData]/~gitbook/auth/login/route.ts
new file mode 100644
index 000000000..3e2362db8
--- /dev/null
+++ b/packages/gitbook/src/app/sites/dynamic/[mode]/[siteURL]/[siteData]/~gitbook/auth/login/route.ts
@@ -0,0 +1,30 @@
+import { type RouteLayoutParams, getDynamicSiteContext } from '@/app/utils';
+import type { NextRequest } from 'next/server';
+import { NextResponse } from 'next/server';
+
+/**
+ * Redirect to the upstream auth provider login URL of site, or to the site root when not configured.
+ */
+export async function GET(
+    request: NextRequest,
+    { params }: { params: Promise<RouteLayoutParams> }
+) {
+    const { context } = await getDynamicSiteContext(await params);
+    const noLoginFallbackURL = context.linker.toAbsoluteURL(context.linker.toPathInSite(''));
+
+    if (!context.site.urls.login) {
+        return NextResponse.redirect(noLoginFallbackURL);
+    }
+
+    try {
+        const loginURL = new URL(context.site.urls.login);
+        const location = request.nextUrl.searchParams.get('location');
+        if (location) {
+            loginURL.searchParams.set('location', location);
+        }
+
+        return NextResponse.redirect(loginURL);
+    } catch (_error) {
+        return NextResponse.redirect(noLoginFallbackURL);
+    }
+}
diff --git a/packages/gitbook/src/components/DocumentView/InlineButton.tsx b/packages/gitbook/src/components/DocumentView/InlineButton.tsx
index 29a4b4e19..5e9e6f956 100644
--- a/packages/gitbook/src/components/DocumentView/InlineButton.tsx
+++ b/packages/gitbook/src/components/DocumentView/InlineButton.tsx
@@ -1,7 +1,10 @@
+import { isSiteAuthLoginHref } from '@/lib/auth-login-link';
 import { resolveContentRefFallback, resolveContentRefInDocument } from '@/lib/references';
 import * as api from '@gitbook/api';
 import type { IconName } from '@gitbook/icons';
+import type React from 'react';
 import { Button, type ButtonProps } from '../primitives';
+import { SiteAuthLoginButton } from '../primitives/SiteAuthLoginLink';
 import type { InlineProps } from './Inline';
 import { InlineActionButton } from './InlineActionButton';
 import { NotFoundRefHoverCard } from './NotFoundRefHoverCard';
@@ -58,21 +61,27 @@ export async function InlineLinkButton(
     const href =
         resolved?.href ??
         (inline.data.ref ? resolveContentRefFallback(inline.data.ref)?.href : undefined);
+    const sharedProps: React.ComponentProps<typeof Button> = {
+        ...buttonProps,
+        insights: {
+            type: 'link_click' as const,
+            link: {
+                target: inline.data.ref,
+                position: api.SiteInsightsLinkPosition.Content,
+            },
+        },
+        href,
+        disabled: href === undefined,
+    };
 
-    const button = (
-        <Button
-            {...buttonProps}
-            insights={{
-                type: 'link_click',
-                link: {
-                    target: inline.data.ref,
-                    position: api.SiteInsightsLinkPosition.Content,
-                },
-            }}
-            href={href}
-            disabled={href === undefined}
-        />
-    );
+    const button =
+        href &&
+        context.contentContext &&
+        isSiteAuthLoginHref(context.contentContext.linker, href) ? (
+            <SiteAuthLoginButton {...sharedProps} />
+        ) : (
+            <Button {...sharedProps} />
+        );
 
     if (inline.data.ref && !resolved) {
         return <NotFoundRefHoverCard context={context}>{button}</NotFoundRefHoverCard>;
diff --git a/packages/gitbook/src/components/Header/HeaderLink.tsx b/packages/gitbook/src/components/Header/HeaderLink.tsx
index a90391b4e..e8d90d19a 100644
--- a/packages/gitbook/src/components/Header/HeaderLink.tsx
+++ b/packages/gitbook/src/components/Header/HeaderLink.tsx
@@ -1,3 +1,4 @@
+import { isSiteAuthLoginHref } from '@/lib/auth-login-link';
 import type { GitBookSiteContext } from '@/lib/context';
 import {
     type ContentRef,
@@ -7,6 +8,7 @@ import {
     SiteInsightsLinkPosition,
 } from '@gitbook/api';
 import assertNever from 'assert-never';
+import type React from 'react';
 
 import { resolveContentRef } from '@/lib/references';
 import { tcls } from '@/lib/tailwind';
@@ -17,6 +19,11 @@ import {
     DropdownMenu,
     DropdownMenuItem,
 } from '../primitives/DropdownMenu';
+import {
+    SiteAuthLoginButton,
+    SiteAuthLoginDropdownMenuItem,
+    SiteAuthLoginLink,
+} from '../primitives/SiteAuthLoginLink';
 
 export async function HeaderLink(props: {
     context: GitBookSiteContext;
@@ -44,6 +51,7 @@ export async function HeaderLink(props: {
                             title={link.title}
                             isDropdown
                             href={target?.href}
+                            isSiteAuthLoginHref={isSiteAuthLoginHref(context.linker, target.href)}
                         />
                     )
                 }
@@ -68,6 +76,7 @@ export async function HeaderLink(props: {
             title={link.title}
             isDropdown={false}
             href={target?.href}
+            isSiteAuthLoginHref={target ? isSiteAuthLoginHref(context.linker, target.href) : false}
         />
     );
 }
@@ -79,6 +88,7 @@ export type HeaderLinkNavItemProps = {
     title: string;
     href?: string;
     isDropdown: boolean;
+    isSiteAuthLoginHref: boolean;
 } & DropdownButtonProps<HTMLElement>;
 
 function HeaderLinkNavItem(props: HeaderLinkNavItemProps) {
@@ -99,7 +109,16 @@ function HeaderItemButton(
         linkStyle: 'button-secondary' | 'button-primary';
     }
 ) {
-    const { linkTarget, linkStyle, headerPreset, title, href, isDropdown, ...rest } = props;
+    const {
+        linkTarget,
+        linkStyle,
+        headerPreset,
+        title,
+        href,
+        isDropdown,
+        isSiteAuthLoginHref,
+        ...rest
+    } = props;
     const variant = (() => {
         switch (linkStyle) {
             case 'button-secondary':
@@ -110,21 +129,25 @@ function HeaderItemButton(
                 assertNever(linkStyle);
         }
     })();
-    return (
-        <Button
-            href={href}
-            variant={variant}
-            size="medium"
-            insights={{
-                type: 'link_click',
-                link: {
-                    target: linkTarget,
-                    position: SiteInsightsLinkPosition.Header,
-                },
-            }}
-            label={title}
-            {...rest}
-        />
+    const sharedProps: React.ComponentProps<typeof Button> = {
+        href,
+        variant,
+        size: 'medium' as const,
+        insights: {
+            type: 'link_click' as const,
+            link: {
+                target: linkTarget,
+                position: SiteInsightsLinkPosition.Header,
+            },
+        },
+        label: title,
+        ...rest,
+    };
+
+    return isSiteAuthLoginHref ? (
+        <SiteAuthLoginButton {...sharedProps} />
+    ) : (
+        <Button {...sharedProps} />
     );
 }
 
@@ -154,20 +177,28 @@ function getHeaderLinkClassName(_props: { headerPreset: CustomizationHeaderPrese
 }
 
 function HeaderItemLink(props: Omit<HeaderLinkNavItemProps, 'linkStyle'>) {
-    const { linkTarget, headerPreset, title, isDropdown, href, ...rest } = props;
-    return (
-        <Link
-            href={href ?? '#'}
-            className={getHeaderLinkClassName({ headerPreset })}
-            insights={{
-                type: 'link_click',
-                link: {
-                    target: linkTarget,
-                    position: SiteInsightsLinkPosition.Header,
-                },
-            }}
-            {...rest}
-        >
+    const { linkTarget, headerPreset, title, isDropdown, href, isSiteAuthLoginHref, ...rest } =
+        props;
+    const sharedProps = {
+        href: href ?? '#',
+        className: getHeaderLinkClassName({ headerPreset }),
+        insights: {
+            type: 'link_click' as const,
+            link: {
+                target: linkTarget,
+                position: SiteInsightsLinkPosition.Header,
+            },
+        },
+        ...rest,
+    };
+
+    return isSiteAuthLoginHref ? (
+        <SiteAuthLoginLink {...sharedProps}>
+            {title}
+            {isDropdown ? <ToggleChevron /> : null}
+        </SiteAuthLoginLink>
+    ) : (
+        <Link {...sharedProps}>
             {title}
             {isDropdown ? <ToggleChevron /> : null}
         </Link>
@@ -204,18 +235,20 @@ async function SubHeaderLink(props: {
         return null;
     }
 
-    return (
-        <DropdownMenuItem
-            href={target.href}
-            insights={{
-                type: 'link_click',
-                link: {
-                    target: link.to,
-                    position: SiteInsightsLinkPosition.Header,
-                },
-            }}
-        >
-            {link.title}
-        </DropdownMenuItem>
+    const sharedProps = {
+        href: target.href,
+        insights: {
+            type: 'link_click' as const,
+            link: {
+                target: link.to,
+                position: SiteInsightsLinkPosition.Header,
+            },
+        },
+    };
+
+    return isSiteAuthLoginHref(context.linker, target.href) ? (
+        <SiteAuthLoginDropdownMenuItem {...sharedProps}>{link.title}</SiteAuthLoginDropdownMenuItem>
+    ) : (
+        <DropdownMenuItem {...sharedProps}>{link.title}</DropdownMenuItem>
     );
 }
diff --git a/packages/gitbook/src/components/Header/HeaderLinkMore.tsx b/packages/gitbook/src/components/Header/HeaderLinkMore.tsx
index 6407d7e7b..ff6b3ef8b 100644
--- a/packages/gitbook/src/components/Header/HeaderLinkMore.tsx
+++ b/packages/gitbook/src/components/Header/HeaderLinkMore.tsx
@@ -1,3 +1,4 @@
+import { isSiteAuthLoginHref } from '@/lib/auth-login-link';
 import type { GitBookSiteContext } from '@/lib/context';
 import {
     type CustomizationContentLink,
@@ -19,6 +20,7 @@ import {
     DropdownMenuSeparator,
     DropdownSubMenu,
 } from '../primitives/DropdownMenu';
+import { SiteAuthLoginDropdownMenuItem } from '../primitives/SiteAuthLoginLink';
 import styles from './headerLinks.module.css';
 
 /**
@@ -84,6 +86,18 @@ async function MoreMenuLink(props: {
     const { context, link } = props;
 
     const target = link.to ? await resolveContentRef(link.to, context) : null;
+    const sharedProps = {
+        href: target?.href,
+        insights: link.to
+            ? {
+                  type: 'link_click' as const,
+                  link: {
+                      target: link.to,
+                      position: SiteInsightsLinkPosition.Header,
+                  },
+              }
+            : undefined,
+    };
 
     return 'links' in link && link.links.length > 0 ? (
         <DropdownSubMenu label={link.title}>
@@ -91,22 +105,11 @@ async function MoreMenuLink(props: {
                 return <MoreMenuLink key={index} {...props} link={subLink} />;
             })}
         </DropdownSubMenu>
-    ) : (
-        <DropdownMenuItem
-            href={target?.href}
-            insights={
-                link.to
-                    ? {
-                          type: 'link_click',
-                          link: {
-                              target: link.to,
-                              position: SiteInsightsLinkPosition.Header,
-                          },
-                      }
-                    : undefined
-            }
-        >
+    ) : isSiteAuthLoginHref(context.linker, target?.href) && sharedProps.href ? (
+        <SiteAuthLoginDropdownMenuItem {...sharedProps} href={sharedProps.href}>
             {link.title}
-        </DropdownMenuItem>
+        </SiteAuthLoginDropdownMenuItem>
+    ) : (
+        <DropdownMenuItem {...sharedProps}>{link.title}</DropdownMenuItem>
     );
 }
diff --git a/packages/gitbook/src/components/primitives/SiteAuthLoginLink.tsx b/packages/gitbook/src/components/primitives/SiteAuthLoginLink.tsx
new file mode 100644
index 000000000..af4faf53c
--- /dev/null
+++ b/packages/gitbook/src/components/primitives/SiteAuthLoginLink.tsx
@@ -0,0 +1,76 @@
+'use client';
+
+import { usePathname, useSearchParams } from 'next/navigation';
+import { useMemo } from 'react';
+import type React from 'react';
+
+import { removeTrailingSlash } from '@/lib/paths';
+import { Button, type ButtonProps } from './Button';
+import { DropdownMenuItem } from './DropdownMenu';
+import { Link, type LinkInsightsProps, type LinkProps } from './Link';
+
+/**
+ * Enrich a site auth login link with the current location relative to the site URL.
+ */
+function useSiteAuthLoginHrefWithLocation(href: string) {
+    const rawPathname = usePathname();
+    const searchParams = useSearchParams();
+    const currentSearch = searchParams?.toString();
+    const pathname = rawPathname ?? '/';
+
+    return useMemo(() => {
+        const baseURL = typeof window !== 'undefined' ? window.location.origin : 'http://localhost';
+        const resolved = URL.canParse(href) ? new URL(href) : new URL(href, baseURL);
+        const siteBasePath = removeTrailingSlash(
+            resolved.pathname.replace(/\/~gitbook\/auth\/login\/?$/, '')
+        );
+        const locationPath =
+            siteBasePath && pathname.startsWith(`${siteBasePath}/`)
+                ? pathname.slice(siteBasePath.length)
+                : pathname === siteBasePath
+                  ? '/'
+                  : pathname;
+
+        resolved.searchParams.set(
+            'location',
+            `${locationPath}${currentSearch ? `?${currentSearch}` : ''}`
+        );
+
+        return href.startsWith('http')
+            ? resolved.toString()
+            : `${resolved.pathname}${resolved.search}`;
+    }, [currentSearch, href, pathname]);
+}
+
+/**
+ * Link component that preserves the current page location through the auth login flow.
+ */
+export function SiteAuthLoginLink(props: LinkProps) {
+    const href = useSiteAuthLoginHrefWithLocation(props.href);
+    return <Link {...props} href={href} />;
+}
+
+/**
+ * Button variant of SiteAuthLoginLink.
+ */
+export function SiteAuthLoginButton(props: ButtonProps) {
+    const href = useSiteAuthLoginHrefWithLocation(props.href ?? '#');
+    return <Button {...props} href={href} />;
+}
+
+/**
+ * Dropdown menu item variant of SiteAuthLoginLink.
+ */
+export function SiteAuthLoginDropdownMenuItem(
+    props: {
+        href: string;
+        target?: React.HTMLAttributeAnchorTarget;
+        active?: boolean;
+        className?: string;
+        children: React.ReactNode;
+        leadingIcon?: React.ReactNode | string;
+    } & LinkInsightsProps
+) {
+    const href = useSiteAuthLoginHrefWithLocation(props.href);
+    return <DropdownMenuItem {...props} href={href} />;
+}
diff --git a/packages/gitbook/src/lib/auth-login-link.test.ts b/packages/gitbook/src/lib/auth-login-link.test.ts
new file mode 100644
index 000000000..6278278b7
--- /dev/null
+++ b/packages/gitbook/src/lib/auth-login-link.test.ts
@@ -0,0 +1,85 @@
+import { describe, expect, it } from 'bun:test';
+import { isSiteAuthLoginHref } from './auth-login-link';
+import { createLinker, linkerForPublishedURL } from './links';
+
+type SiteFixture = {
+    label: string;
+    publishedURL: string;
+    siteBasePath: string;
+    localhostLoginURL: string;
+    previewLoginURL: string;
+    publishedLoginURL: string;
+};
+
+const previewHost = '41ba7c7e-gitbook-open-v2-preview.gitbook.workers.dev';
+const fixtures: SiteFixture[] = [
+    {
+        label: 'proxy sites',
+        publishedURL: 'https://gitbook.com/docs',
+        siteBasePath: '/url/gitbook.com/docs',
+        localhostLoginURL: 'https://localhost:3000/url/gitbook.com/docs/~gitbook/auth/login',
+        previewLoginURL: `https://${previewHost}/url/gitbook.com/docs/~gitbook/auth/login`,
+        publishedLoginURL: 'https://gitbook.com/docs/~gitbook/auth/login',
+    },
+    {
+        label: 'GitBook-hosted site with a path prefix',
+        publishedURL: 'https://gitbook.gitbook.io/test/',
+        siteBasePath: '/url/gitbook.gitbook.io/test',
+        localhostLoginURL: 'https://localhost:3000/url/gitbook.gitbook.io/test/~gitbook/auth/login',
+        previewLoginURL: `https://${previewHost}/url/gitbook.gitbook.io/test/~gitbook/auth/login`,
+        publishedLoginURL: 'https://gitbook.gitbook.io/test/~gitbook/auth/login',
+    },
+    {
+        label: 'custom domain at the root path',
+        publishedURL: 'https://docs.acme.org/',
+        siteBasePath: '/url/docs.acme.org',
+        localhostLoginURL: 'https://localhost:3000/url/docs.acme.org/~gitbook/auth/login',
+        previewLoginURL: `https://${previewHost}/url/docs.acme.org/~gitbook/auth/login`,
+        publishedLoginURL: 'https://docs.acme.org/~gitbook/auth/login',
+    },
+];
+
+function createURLModeSiteLinker(currentHost: string, siteBasePath: string, publishedURL: string) {
+    const linker = createLinker({
+        protocol: 'https:',
+        host: currentHost,
+        siteBasePath,
+        spaceBasePath: `${siteBasePath}/getting-started`,
+    });
+
+    return linkerForPublishedURL(linker, publishedURL);
+}
+
+describe('isSiteAuthLoginHref', () => {
+    describe.each(fixtures)('$label', (fixture) => {
+        it('matches the localhost absolute login URL for the current site', () => {
+            const linker = createURLModeSiteLinker(
+                'localhost:3000',
+                fixture.siteBasePath,
+                fixture.publishedURL
+            );
+
+            expect(isSiteAuthLoginHref(linker, fixture.localhostLoginURL)).toBe(true);
+        });
+
+        it('matches the workers preview absolute login URL for the current site', () => {
+            const linker = createURLModeSiteLinker(
+                previewHost,
+                fixture.siteBasePath,
+                fixture.publishedURL
+            );
+
+            expect(isSiteAuthLoginHref(linker, fixture.previewLoginURL)).toBe(true);
+        });
+
+        it('matches the published-site absolute login URL when served through preview', () => {
+            const linker = createURLModeSiteLinker(
+                previewHost,
+                fixture.siteBasePath,
+                fixture.publishedURL
+            );
+
+            expect(isSiteAuthLoginHref(linker, fixture.publishedLoginURL)).toBe(true);
+        });
+    });
+});
diff --git a/packages/gitbook/src/lib/auth-login-link.ts b/packages/gitbook/src/lib/auth-login-link.ts
new file mode 100644
index 000000000..a0d081b8d
--- /dev/null
+++ b/packages/gitbook/src/lib/auth-login-link.ts
@@ -0,0 +1,36 @@
+import type { GitBookLinker } from './links';
+import { removeTrailingSlash } from './paths';
+
+/**
+ * Check if an href points to the current site's auth login route.
+ */
+export function isSiteAuthLoginHref(
+    linker: Pick<GitBookLinker, 'toPathInSite' | 'toAbsoluteURL' | 'toLinkForContent'>,
+    href?: string | null
+) {
+    if (!href) {
+        return false;
+    }
+
+    const relativeLoginHref = linker.toPathInSite('~gitbook/auth/login');
+    const absoluteLoginHref = linker.toAbsoluteURL(relativeLoginHref);
+    const siteRelativeHref = URL.canParse(href) ? linker.toLinkForContent(href) : href;
+
+    return (
+        normalizeHref(href) === normalizeHref(relativeLoginHref) ||
+        normalizeHref(href) === normalizeHref(absoluteLoginHref) ||
+        normalizeHref(siteRelativeHref) === normalizeHref(relativeLoginHref)
+    );
+}
+
+/**
+ * Normalize an href so login-route comparisons ignore trailing slashes.
+ */
+function normalizeHref(href: string) {
+    if (URL.canParse(href)) {
+        const url = new URL(href);
+        return `${url.origin}${removeTrailingSlash(url.pathname)}`;
+    }
+
+    return removeTrailingSlash(href);
+}
diff --git a/packages/gitbook/src/lib/sites.ts b/packages/gitbook/src/lib/sites.ts
index 347be9c50..c6f6d0c02 100644
--- a/packages/gitbook/src/lib/sites.ts
+++ b/packages/gitbook/src/lib/sites.ts
@@ -1,6 +1,6 @@
 import type { GitBookSiteContext } from '@/lib/context';
 import type {
-    LocalizedString,
+    LocalizedTitle,
     SiteSection,
     SiteSectionGroup,
     SiteSpace,
@@ -189,7 +189,7 @@ function findSiteSpaceByIdInSiteSpaces(
  * Get the localized title for a site entity (SiteSection, SiteSectionGroup, or SiteSpace).
  */
 export function getLocalizedTitle(
-    entity: { title: string; localizedTitle?: LocalizedString },
+    entity: { title: string; localizedTitle?: LocalizedTitle },
     currentLanguage: TranslationLanguage | undefined
 ): string {
     return getLocalizedField(entity.localizedTitle, currentLanguage) ?? entity.title;
@@ -199,7 +199,7 @@ export function getLocalizedTitle(
  * Get the localized description for a site entity.
  */
 export function getLocalizedDescription(
-    entity: { description?: string; localizedDescription?: LocalizedString },
+    entity: { description?: string; localizedDescription?: LocalizedTitle },
     currentLanguage: TranslationLanguage | undefined
 ): string | undefined {
     return getLocalizedField(entity.localizedDescription, currentLanguage) ?? entity.description;
@@ -209,7 +209,7 @@ export function getLocalizedDescription(
  * Get a localized field value for the given language.
  */
 function getLocalizedField(
-    localizedField: LocalizedString | undefined,
+    localizedField: LocalizedTitle | undefined,
     currentLanguage: TranslationLanguage | undefined
 ): string | undefined {
     if (localizedField && currentLanguage && localizedField[currentLanguage]) {
diff --git a/packages/gitbook/src/middleware.ts b/packages/gitbook/src/middleware.ts
index 11cdc5484..3a0b32d94 100644
--- a/packages/gitbook/src/middleware.ts
+++ b/packages/gitbook/src/middleware.ts
@@ -681,8 +681,9 @@ function encodePathInSiteContent(
             return { pathname, routeType: 'static' };
         case '~gitbook/pdf':
         case '~gitbook/search':
+        case '~gitbook/auth/login':
         case '~scalar/proxy':
-            // PDF and search routes are always dynamic as they depend on the request.
+            // PDF, search and auth routes are always dynamic as they depend on the request.
             return { pathname, routeType: 'dynamic' };
         default: {
             // If the pathname is a markdown file or the request is accepting markdown,